Municipal sewage waste imposes significant environmental and handling costs, including damage to water and air quality. This problem has intensified with population growth and suburbanization. Significant time and energy inputs may be needed to process water and solids to (a) return clean water to surface waters and (b) render solid or liquid materials suitable for agricultural use.
In a standard process, wastewater enters the treatment plant and is treated via a series of large pools. In primary sewage pools, oil and grease are removed, and water in the waste begins to evaporate. In secondary pools, the water is further agitated and aerated. This promotes activity in the pool to release more water via evaporation and cause the waste to react to the air. In final pools, aeration continues, and treatment is concluded. The end wastewater product is malodorous but is only 1.5% solids on average.
In some locales, cities will arrange for the wastewater product to be hauled away, with it then being spread on fields as fertilizer. Environmental protection authorities often disfavor this handling because of risk to surface waters and groundwater as well as air quality. In addition, the waste may contain viruses and bacteria or other infectious microorganisms. Open field spreading of municipal waste can also result in municipal liability in the event of any environmental damage.
In some areas of the world, the processing of fresh fruit bunches of oil palm results in the generation of different types of residue. Among the waste generated, palm oil mill effluent (POME) is considered the most harmful waste for the environment if discharged untreated. POME is the wastewater discharged from the sterilization process, crude oil clarification process, and cracked mixture separation process. It results in clogging and water logging of the soil and kills any vegetation on contact. Currently, the most suitable, and frequently used, treatment method is a ponding system. However, ponding systems occupy a vast amount of landmass, have a relatively long hydraulic retention time, a bad odor, and difficult in maintaining the liquor distribution and biogas collection.
Access to an efficient source of biomass fuel is also a critical issue. Current biomass competition includes coal, wood pellets, natural gas and nuclear processes for production of energy. However, various markets, including Europe, have imposed fuel taxes based on carbon content (such as in coal and natural gas) or have mandated the use of clean energy sources such as biomass. Wood fiber resources are not sufficient to meet this demand. Processed human or animal waste products could provide a renewable and plentiful source of biomass fuel. However, current processing of such waste processing into fuel pellets involves substantial time, energy, transport fuel and labor inputs and charges. Use of these fuel pellets results in a net energy loss. With transport, the environmental issues are compounded because of the addition of truck fuel air pollution associated with moving heavy, high-moisture waste on the road.
Systems and methods are needed that (a) minimize human waste exposure to air and chance of waste release into surface water or groundwater and (b) reduce energy processing for both clean water and fertilizer and/or fuel pellets. Generally, a system is needed to efficiently and rapidly remove liquid from human waste and speed processing into clean water, fertilizer and/or fuel.